The solution method for forming a function layer (such as a hole injection layer, a hole transporting layer, a light-emitting layer, an electron transporting layer, and an electron injection layer) of an organic electroluminescent device includes: the material of the function layer is first prepared to be a solution, the solution is then coated by spinning or spraying to form the function layer, and after that it is dried at room temperature. During the drying and film forming process for the function layer, solvent will be remained, which leads to a poor dense and non-uniform function layer, and easily results in defects, especially when the function layer is a light-emitting layer, host and guest molecules in a doped system are easy to aggregate, and cannot merge into each other well, so the energy transfer and the carrier transport capability between the host and guest materials are affected.